class Solution(object):
    def findRepeatedDnaSequences(self, s):
        """
        :type s: str
        :rtype: List[str]
        """
        dnas = set()
        results = set()
        for i in range(0, len(s)-9):
            dna = str(s[i:i+10])
            if dna not in dnas: dnas.add(dna)
            else: results.add(dna)
        return list(results)

print(Solution().findRepeatedDnaSequences("AAAAAAAAAAA"))